The invention relates to a printed article and a feedstock, i.e. a raw material for printing, in which glass is a filler material. Particularly, the invention is concerned with printed articles comprising a polymeric material. The invention also relates to a process of manufacturing the feedstock and a process of printing using the feedstock.
In known shaping processes, such as two-dimensional printing and three-dimensional printing (3D printing), a feedstock composition comprises a matrix forming material such as a polymeric material, i.e. synthetic resin, and a filler material. Feedstock types include a liquid, activated by UV light; a powder, activated by a liquid activation agent; and a filament, melted and deposited in a desired shape, which then solidifies. Additive depositing of a resin composition allows rapid manufacturing of 3D objects. Solid state devices may be printed in 2D or 3D, optionally with more than one feedstock.
EP0931273B1 (Qinetiq/Shepherd) discloses a shaping process for articles characterised by dimensional and dielectric properties suitable for a waveguide. Stereolithography apparatus (SLA) is used to shape liquid resin, curable by exposure to ultraviolet laser light. The laser light causes highly accurate localised polymerisation of a batch monomer. A resulting object is an epoxy resin lattice, having low permittivity (relative dielectric constant of 3). A high permittivity material (relative dielectric constant 12.5) is cast in voids of the lattice. Thus a dielectric medium is formed, having two materials with discrete interfaces between them. Such a medium is capable of functioning as a block of photonic crystal, i.e. a material which is reflective to incident radiation within a predetermined band gap, at all angles, with no internal loss, in a microwave frequency range 2 GHz to 30 GHz.
EP1628823B1 (Z Corporation/Bredt) discloses a shaping process to build three-dimensional articles from successive thin layers. Each layer is formed from a powder mixture of a polymeric particulate material and an adhesive particulate material. Each layer is bonded to a previously formed layer at the same time as the particles of each layer are bonded together. Bonding is by use of a binder fluid, delivered by an ink-jet printing head. Optionally the powder mixture may comprise a filler material for improved mechanical structure. An example of a filler material is soda-lime glass having particle grain diameter between 5 um and 100 um.
Suwanprateeb in J Mater Sci: Mater Med (2009) 20:1281-1289 discloses printed articles for bone replacement using a 3D printer Z400 available from Z Corporation, Burlington Mass., USA. A powder mixture comprising apatite-wollastonite (A-W) glass powder is used to print a green specimen, which is then sintered in an electrical furnace. The mean particle size of the A-W glass powder is approximately 88 um.
U.S. Pat. No. 7,049,363B2 (Daimler/Shen) discloses a feedstock for use in 3D printing. The feedstock comprises a filler material, such as a ceramic, mixed with a polymeric binder material in a solvent. Fine spherical particles of filler and binder are preferred. Articles printed with this feedstock are said to have high shape stability and strength.
US2011012960A1 (Corning/Beall) discloses a process to make a porous article by 3D printing. In a first step, a batch composition, comprising a structural powder and a binder powder, is deposited to form a powder mixture layer. In a second step, an aqueous liquid contacts the layer to selectively activate the binder powder. Depositing and contacting steps are repeated until the required shape is formed. The structural powder may be comprised of glass, having an average particle size of less than 15 um.
U.S. Pat. No. 6,437,034B2 (Stratasys/Lombardi) and U.S. Pat. No. 8,227,540B2 (Stratasys/Priedeman) each discloses a resin composition for making a printed article by 3D printing, comprising a polymer blended with filler material such as glass spheres or glass fibre. Polymers include acrylonitrile-butadiene-styrene, i.e. ABS. The composition is extruded to form a cylindrical rod feedstock or a filament feedstock for a 3D printer. Examples of a suitable printing apparatus include Stratasys Fused Deposition Modelling (FDM) 3D printers.
EP2017300B1 (Nippon Sheet Glass/Yagyu) discloses a thermoplastic resin composition for moulded product, comprising a glass flake filler. The moulded product is said to have high strength and good dimensional stability. When the resin composition is extruded, glass flake filler is said to be oriented along the flowing direction of the resin composition. Glass flakes in the resin composition are thinner than conventional glass flakes, i.e. thickness is in a range from 0.05 um to 1.0 um. Average thickness is in a range from 0.1 um to 0.4 um. Average diameters of the glass flakes are in a range from 20 to 150 um. Optionally, glass flakes are granulated using a binder so that average granular particle size is 200 um. The resin composition is moulded by pouring into a metallic mould or is extruded to form pellets, and the pellets are moulded into a product using an injection moulding machine.
It is an object of the present invention to provide an alternative printed article and a feedstock, and corresponding processes of manufacturing the feedstock and of printing using the feedstock, in which glass is a filler material.